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1
BERGAMIN, L., e D. GRUMILLER. "KILLING HORIZONS KILL HORIZON DEGREES". International Journal of Modern Physics D 15, n. 12 (dicembre 2006): 2279–84. http://dx.doi.org/10.1142/s0218271806009571.
Testo completoAbstract (sommario):
Frequently, it is argued that the microstates responsible for the Bekenstein–Hawking entropy should arise from some physical degrees of freedom located near or on the black hole horizon. In this essay, we elucidate that instead entropy may emerge from the conversion of physical degrees of freedom, attached to a generic boundary, into unobservable gauge degrees of freedom attached to the horizon. By constructing the reduced phase space, it can be demonstrated that such a transmutation indeed takes place for a large class of black holes, including Schwarzschild.
2
Lou, Yihuai, Bo Zhang, Tengfei Lin e Danping Cao. "Seismic horizon picking by integrating reflector dip and instantaneous phase attributes". GEOPHYSICS 85, n. 2 (30 gennaio 2020): O37—O45. http://dx.doi.org/10.1190/geo2018-0303.1.
Testo completoAbstract (sommario):
Seismic horizons are the compulsory inputs for seismic stratigraphy analysis and 3D reservoir modeling. Manually interpreting horizons on thousands of vertical seismic slices of 3D seismic survey is a time-consuming task. Automatic horizon interpreting algorithms are usually based on the seismic reflector dip. However, the estimated seismic reflector dip is usually inaccurate near and across geologic features such as unconformities. We are determined to improve the quality of picked horizons using multiple seismic attributes. We assume that seismic horizons follow the reflector dip and that the same horizons should have similar instantaneous phase values. We first generate horizon patches using a reflector dip attribute, which is similar to current methods. We use seismic coherence attribute as the stop criteria for tracking the horizon within each patch. Considering the inaccuracy of reflector dip estimates at and near the discontinuous structures such as fault and unconformities, we use the seismic instantaneous phase attribute to improve the quality of the generated horizon patches. We generate horizons by merging the residual horizon patches and only outputting the best horizon in each iteration. Our method is capable of generating a horizon for each reflection within the 3D seismic survey, and the generated horizons strictly follow the seismic reflections over the whole seismic survey. Finally, each time sample of seismic traces is assigned a chronostratigraphic relative geologic time value according to the tracked horizons.
3
Lou, Yihuai, Bo Zhang, Huijing Fang, Danping Cao, Kangning Wang e Zhizhou Huo. "Simulating the procedure of manual seismic horizon picking". GEOPHYSICS 86, n. 1 (1 gennaio 2021): O1—O12. http://dx.doi.org/10.1190/geo2020-0021.1.
Testo completoAbstract (sommario):
Manual seismic horizon picking is the least efficient interpretation technique in terms of time and effort. The loop-tie is a key “element” and the most time-consuming task in manual horizon picking, which ensures the accuracy of horizon picking. Autopicking techniques have been used since the early 1980s. However, there are few studies simulating the procedure of manual seismic horizon picking and quantitatively evaluating the autopicked horizons. In our proposed method, we perform autopicking on inline and crossline seismic vertical slices independently, similar to the manual horizon picking procedure. We then evaluate the picked horizons using a loop-tie step similar to the loop-tie checking in manual horizon picking. To simulate the loop-tie step in manual picking, we define two dip attributes for each time sample of seismic traces, which are the “left” and “right” reflector dips. We only preserve the portions of the tracked horizons that meet the defined loop-tie checking. Next, we merge the tracked horizons centered at the seeded seismic traces. The two-way traveltime of the merged horizons functions as a “hard” control for the final step of autopicking. Finally, we use the seismic dip attribute to track the horizons over the seismic survey under the hard controls. The real data demonstrate that our algorithm can extract accurate horizons near discontinuities such as faults and unconformities.
4
Almeida, Jaime Antonio de, Denis Cesar Cararo e Antônio Ayrton Auzani Uberti. "Genesis of the sombric horizon in ultisols (red argisols) in southern Santa Catarina, Brazil". Revista Brasileira de Ciência do Solo 33, n. 2 (aprile 2009): 405–16. http://dx.doi.org/10.1590/s0100-06832009000200018.
Testo completoAbstract (sommario):
Dark subsurface horizons, with properties similar to the sombric horizon characterized by the USA Soil Taxonomy, are frequent in Southern Brazil. The genesis of this horizon is controversial and poorly understood. This study aimed to describe the occurrence of sombric-like horizons in Ultisols in the South of Santa Catarina State, at low altitudes, and suggest possible processes of humus transference, accumulation and persistence in these horizons. Physical, chemical and mineralogical properties of four Ultisols were evaluated; three were sampled in a toposequence, and another representative one in an isolated profile (RSP). The dark subsurface horizons coincide with the AB and BA transitional genetic horizons; they are acid, low in base saturation, and have a similar clay mineralogy in all horizons. Very high amounts of Fe and Al extracted by ammonium oxalate and sodium pyrophosphate solution as well as maximum Al extracted by CuCl2 solution were observed in these dark subsurface horizons, indicating a possible migration of these elements in the form of organometallic complexes. The contents of Al plus ½ Fe extracted from the RSP soil horizons with ammonium oxalate indicated spodic materials in the sombric-like horizon, although the soil morphology was not compatible with Spodosols. Maximum contents of fine clay were also found in the sombric-like horizon, suggesting Fe and Al migration as clay-humic substances. However, the hypothesis that sombric-like horizons in these soils are a relict feature of a grass paleovegetation, different from the current dense seasonal forest, should not be discarded but investigated in further studies.
5
Chakraborty, Subenoy, e Subhajit Saha. "A study of different horizons in inhomogeneous LTB cosmological model". Modern Physics Letters A 30, n. 09 (11 marzo 2015): 1550024. http://dx.doi.org/10.1142/s0217732315500248.
Testo completoAbstract (sommario):
This work deals with a detailed study of the dynamics of the apparent, event and particle horizons in the background of the inhomogeneous LTB spacetime. The comparative study among these horizons shows a distinct character for apparent horizon compared to the other horizons. The apparent horizon will be a trapping horizon if its acceleration is positive. The Kodama vector is also defined and its causal character is found to be similar to that in the FRW model.
6
Fil’chenkov, M. L., e Yu P. Laptev. "Vacuum Polarization and Particle Creation for Two-Horizon Metrics". Journal of Physics: Conference Series 2081, n. 1 (1 novembre 2021): 012018. http://dx.doi.org/10.1088/1742-6596/2081/1/012018.
Testo completoAbstract (sommario):
Abstract Kerr–Newman and Kottler’s metrics with two horizons are considered. Evaporation of Kerr – Newman’s horizons in Hawking’s effect and Penrose’s process as well as de Sitter’s horizon decay and Schwarzschild’s horizon evaporation for Kottler’s metric have been analyzed in terms of an effective temperature, using lifetimes on the horizons. The results are applied to black hole physics and cosmology.
7
Wang, C., G. R. Brewster e K. T. Webb. "Micromorphological evidence of pedogenetic pathway of a Podzolic Gray Luvisol (Falmouth series) in Nova Scotia". Canadian Journal of Soil Science 75, n. 4 (1 novembre 1995): 491–96. http://dx.doi.org/10.4141/cjss95-070.
Testo completoAbstract (sommario):
A catena of Podzolic Gray Luvisols (Falmouth series) – Gleyed Gray Luvisols (Queens series) – Orthic Gleysols (Kingsville series) is commonly found on fine loamy, weakly calcareous parent materials in Nova Scotia, with Podzolic Gray Luvisols occupying the best drained landscape positions. The hypothesis that podzolic B horizons of Podzolic Gray Luvisols were developed on degraded Bt horizons was investigated by micromorphological characterization of one Podzolic Gray Luvisol pedon. Although not visible in field examinations, argillans were common in thin sections of the Bf and Bm horizons. These argillans were not associated with the walls of voids or the surface of grains. Argillans of the Bt horizons, however, were associated with features such as cracks, vughs, and channels. The upper Bt horizon (i.e., Bt1gj) showed signs of degradation. The pale brown matrix color was more like the Bm horizon above than the dark brown Bt2gj horizon below. The strongly acidic nature of the Bt1gj horizon may have triggered degradation. It is concluded that the Bf and Bm horizons were developed on degraded Bt horizons through the translocation of amorphous Fe and Al and organic matter. Key words: Pedogenesis, micromorphology, Luvisols, bisequal soils
8
Baccetti, Valentina, Robert B. Mann e Daniel R. Terno. "Do event horizons exist?" International Journal of Modern Physics D 26, n. 12 (ottobre 2017): 1743008. http://dx.doi.org/10.1142/s0218271817430088.
Testo completoAbstract (sommario):
Event horizons are the defining feature of classical black holes. They are the key ingredient of the information loss paradox which, as paradoxes in quantum foundations, is built on a combination of predictions of quantum theory and counterfactual classical features: neither horizon formation nor its crossing by a test body can be detected by a distant observer. Furthermore, horizons are unnecessary for the production of Hawking-like radiation. We demonstrate that when this radiation is taken into account, it can prevent horizon crossing/formation in a large class of models. We conjecture that horizon avoidance is a general feature of collapse. The nonexistence of event horizons dispels the paradox, but opens up important questions about thermodynamic properties of the resulting objects and correlations between different degrees of freedom.
9
NIELSEN, ALEX B. "BLACK HOLES WITHOUT BOUNDARIES". International Journal of Modern Physics D 17, n. 13n14 (dicembre 2008): 2359–66. http://dx.doi.org/10.1142/s0218271808014205.
Testo completoAbstract (sommario):
We discuss some of the drawbacks of using event horizons to define black holes and suggest ways in which black holes can be described without event horizons, using trapping horizons. We show that these trapping horizons give rise to thermodynamic behavior and possibly Hawking radiation too. This raises the issue of whether the event horizon or the trapping horizon should be seen as the true boundary of a black hole. This difference is important if we believe that quantum gravity will resolve the central singularity of the black hole and clarifies several of the issues associated with black hole thermodynamics and information loss.
10
Palenzuela, Nilo. "Entre Horizontes Insulares/Among Insular Horizons". Third Text 28, n. 4-5 (22 agosto 2014): 345–60. http://dx.doi.org/10.1080/09528822.2014.939838.
Testo completo
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Perdomo, Carolina V., Lidiane C. Nogueira, Miriam G. Miguel e Francisco S. B. Ladeira. "Analysis of water retention in soil horizons of two open trenches on a slope of Serra do Mar, Brazil, susceptible to landslides". MATEC Web of Conferences 337 (2021): 03015. http://dx.doi.org/10.1051/matecconf/202133703015.
Testo completoAbstract (sommario):
This research presents and analyzes the results of Soil Water Characteristic Curves (SWCC) for the soil horizons (A, B and C) of two different trenches (TR3 and TR7) opened along a slope located in the Serra da Mar mountain range, Brazil. Microaggregations were observed in soil horizons of both trenches, which changed the textural classification of the soils. TR7 showed more macropores than TR3, especially on horizon C. Unimodal SWCC were obtained for soils of the horizon A for both trenches. Instead, bimodal SWCC were obtained for soils of the deeper horizons (B and C). All soil horizons showed the phenomenon of hysteresis, and it’s more expressive in the macroporosity part. In TR7 the water retention capacity is lower in B and C, facilitating the drainage, however, horizons B and C of TR3 presented greater water retention capacity for the same matric suction value. Depending on the intensity and duration of rainfall, the horizons B and C of both trenches may suffer a decrease of shear strength, without necessarily saturating. The A horizon of TR3 can undergo an erosive process for heavy and short rains.
12
Li, Shaobo, Jianhu Zhao, Hongmei Zhang e Siheng Qu. "An Integrated Horizon Picking Method for Obtaining the Main and Detailed Reflectors on Sub-Bottom Profiler Sonar Image". Remote Sensing 13, n. 15 (28 luglio 2021): 2959. http://dx.doi.org/10.3390/rs13152959.
Testo completoAbstract (sommario):
A sub-bottom profiler (SBP) can capture the sediment interfaces and properties of different types of sediment. Horizon picking from SBP images is one of the most crucial steps in marine sub-bottom sediment interpretation. However, traditional horizon picking methods are good at obtaining the main horizons representing the main reflectors while ignoring the detailed horizons. While detailed horizons are the prime objective, many tiny structures caused by interference echoes will also be picked. To overcome this limitation, an integrated horizon picking method for obtaining the main and detailed horizons simultaneously is proposed in this paper. A total of three main process steps: the diffusion filtering method, the enhancement filtering method as well as the local phase calculation method, are used to help obtain the main and detailed horizons. The diffusion filtering method smooths the SBP images and preserves reflectors. Enhancement filtering can eliminate outliers and enhance reflectors. The local phase can be used to highlight all of the reflections and help in the choosing of detailed horizons. A series of experiments were then performed to validate the effectiveness of the proposed method, and good performances were achieved.
13
LOWE, L. E., A. M. SCAGEL e K. KLINKA. "CHEMICAL PROPERTIES AND CLASSIFICATION OF ORGANIC HORIZONS FROM SELECTED SOILS IN BRITISH COLUMBIA". Canadian Journal of Soil Science 67, n. 2 (1 maggio 1987): 383–94. http://dx.doi.org/10.4141/cjss87-033.
Testo completoAbstract (sommario):
In order to assess the extent to which chemical properties of organic horizons support their differentiation on the basis of morphological characteristics, as used in the Canadian System of Soil Classification (CSSC), a total of 265 samples of organic horizons (including L, F, H, Of, Om and Oh) were analyzed for 26 chemical properties (organic and inorganic). One-way analysis of variance, correlation analysis and tests of normality were used to select variables for canonical variates analysis (CVA). The results of CVA indicated that the six types of horizon could be distinguished by a combination of chemical properties, and that the grouped upland (L-F-H) horizons could be distinguished from the grouped wetland (Of-Om-Oh) horizons. The results provided support for the present usage in the CSSC, based on field morphology. It was concluded that there remained a need to improve definitions, to review designations, and to develop quantitative diagnostic criteria for organic horizons. Some problems in the classification of organic horizons are discussed, particularly in relation to a hierarchical system. Key words: Organic horizons, horizon classification, British Columbia, chemical properties
14
Mars, Marc, Tim-Torben Paetz e José M. M. Senovilla. "Multiple Killing horizons and near horizon geometries". Classical and Quantum Gravity 35, n. 24 (19 novembre 2018): 245007. http://dx.doi.org/10.1088/1361-6382/aaeaf1.
Testo completo
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Georges, T. M., e J. A. Harlan. "New horizons for over-the-horizon radar?" IEEE Antennas and Propagation Magazine 36, n. 4 (agosto 1994): 14–24. http://dx.doi.org/10.1109/74.317763.
Testo completo
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Debnath, Ujjal. "Entropy bound of horizons of some regular black holes". Modern Physics Letters A 35, n. 10 (17 gennaio 2020): 2050070. http://dx.doi.org/10.1142/s0217732320500704.
Testo completoAbstract (sommario):
We study the four-dimensional (i) modified Bardeen black hole, (ii) modified Hayward black hole, (iii) charged regular black hole and (iv) magnetically charged regular black hole. For modified Bardeen black hole and modified Hayward black hole, we found only one horizon (event horizon) and then we found some thermodynamic quantities like the entropy, surface area, irreducible mass, temperature, Komar energy and specific heat capacity on the event horizon. We here study the bounds of the above thermodynamic quantities for these black holes on the event horizon. Then, we examine the thermodynamics stability of the black holes with some conditions. Next, we studied the charged regular black hole and magnetically charged regular black hole and found two horizons (Cauchy and event horizons) of these black holes. Then, we found the entropy, surface area, irreducible mass, temperature, Komar energy and specific heat capacity on the Cauchy and event horizons. Then, we get some conditions for thermodynamic stability/instability of the black holes. We found the radius of the extremal horizon and Christodoulou–Ruffiini mass and then analyze the above thermodynamic quantities on the extremal horizon. We calculate the sum/subtraction, product, division and sum/subtraction of inverse of surface areas, entropies, irreducible masses, temperatures, Komar energies and specific heat capacities on both the horizons. From these, we found the bounds of the above quantities on the horizons.
17
Joshi, Yash Pal. "The Desirability Index: A Measure For The Desirability Of Stocks Over Bonds Over The Long Term". Journal of Applied Business Research (JABR) 10, n. 1 (27 settembre 2011): 62. http://dx.doi.org/10.19030/jabr.v10i1.5964.
Testo completoAbstract (sommario):
<span>One of the long held beliefs in the field of investments is that stocks are more desirable as compared to bonds for long horizon portfolios. But how long is the long horizon? This paper defines two summary measuresthe Desirability Index and the Cutoff Horizonto measure the desirability of stocks over bonds, and concludes that, based on historical performance, stocks are more desirable than bonds for horizons longer than 15 years.</span>
18
Stotyn, Sean. "A tale of two horizons". Canadian Journal of Physics 93, n. 9 (settembre 2015): 995–98. http://dx.doi.org/10.1139/cjp-2015-0091.
Testo completoAbstract (sommario):
I revisit the fate of coinciding horizons and the volume between them in the extremal limit of spherically symmetric black holes in four space–time dimensions, focusing on the Schwarzschild – de Sitter black hole for concreteness. The two Killing horizons in the limit space–time that are traditionally identified with the limiting event horizons of the non-extremal black hole are shown to instead be generated by an enhanced symmetry of the near horizon geometry (NHG). This dismantles the interpretation of the four-volume between the horizons remaining finite in the extremal limit. The NHG is reinterpreted as a tangent space–time to the degenerate black hole horizon, and geometrical objects, such as Killing vectors and Killing horizons, are carefully mapped between the bulk and the NHG. The implications for extremal black hole entropy are then discussed.
19
Vallée, Michel. "New Horizons / Nouveaux horizons". Forestry Chronicle 89, n. 02 (aprile 2013): 124–26. http://dx.doi.org/10.5558/tfc2013-025.
Testo completo
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Batista, Gustavo Silvano. "Compreensão, Fusão de Horizontes e Filosofia Prática/Understanding, Fusion of Horizons and Practical Philosophy". Pensando - Revista de Filosofia 7, n. 14 (4 febbraio 2016): 94. http://dx.doi.org/10.26694/pensando.v6i12.4543.
Testo completoAbstract (sommario):
O acontecimento do compreender, enquanto questão-chave do pensamento de Gadamer, também pode ser compreendido como uma fusão de horizontes. Do ponto de vista da hermenêutica filosófica, tal aspecto abre a possibilidade de tematização do âmbito próprio da compreensão como uma experiência filosófica simultaneamente ontológica e prática. Por isso, a descrição do compreender enquanto fusão de horizontes indica o tratamento de traços fundamentais da vida humana que, para Gadamer, encontra afinidades com a retomada da filosofia prática de Aristóteles. Deste modo, pretendemos discutir alguns aspectos da relação entre os conceitos de compreensão e fusão de horizonte a partir da conexão essencial entre hermenêutica filosófica e filosofia prática.Abstract: The happening of understanding, as key-issue of Gadamer’s thought, can be also understood like a fusion of horizons. From the point of view of philosophical hermeneutics, this aspect opens the possibility of discussing about the sphere of understanding simultaneously ontological and practice philosophical experience. Therefore, the description of understanding as fusion of horizons indicates the treatment of basic traces of human life that finds affinities with the rehabilitation of practical philosophy of Aristotle. Thus, we intend to discuss some aspects of the relation between the notions of understanding and fusion of horizons from the essential connection between philosophical hermeneutics and practical philosophy. Keywords: Gadamer; understanding; fusion of horizons; practical philosophy; Aristotle.
21
Tagiverdiev, Suleiman S., Pavel N. Skripnikov, Olga S. Bezuglova, Sergey N. Gorbov e Denis A. Kozyrev. "Content and Distribution of Organic And Inorganic Carbon in the Urban Soils of Rostov Agglomeration". UNIVERSITY NEWS. NORTH-CAUCASIAN REGION. NATURAL SCIENCES SERIES, n. 4 (208) (23 dicembre 2020): 118–29. http://dx.doi.org/10.18522/1026-2237-2020-4-118-129.
Testo completoAbstract (sommario):
The content and distribution of organic and inorganic carbon along the profile in the soils of the Rostov agglomeration are considered. The results obtained on a TOC-L CPN Shimadzu carbon analyzer are evaluated using Student's t-test. The groups of some horizons of native soils AU rz, AU, BCA, C, as well as their buried analogues [AU], [BCA], [C] were compared. The analysis of the urbic horizons was carried out taking into account their particle size distribution, previously dividing into horizons clusters - heavy URh and light URl. In the [AU] horizon of soils buried under the anthropogenic stratum, a statistically significant decrease in the organic carbon content is observed, compared to the AU horizon of natural analogues. The middle part of the profile - the BCA and [BCA] horizons - is characterized by the greatest similarity in carbon content, both organic and inorganic, which suggests the lowest anthropogenic impact on these horizons. Significant differences in the inorganic carbon content in the comparison pair - horizons C and [C] are shown, and its content is higher in natural analogues (horizons C). The data analysis of the urbic diagnostic horizons did not reveal any significant regularities because of the high degree of variation of this indicator due to the genesis peculiarities of the anthropogenically transformed stratum.
22
Voloshyn, P. "The estimation of natural protectability and vulnerability of ground water to anthropogenic pollution within territory of Lviv". Visnyk of the Lviv University. Series Geography 1, n. 40 (12 dicembre 2012): 149–55. http://dx.doi.org/10.30970/vgg.2012.40.2039.
Testo completoAbstract (sommario):
The main groundwater horizons of Lviv area are characterized. The key factors of their protectability and vulnerability are analyzed. Natural pro-tectability of of different age aquiferous horizons was estimated. Least protected from pollution are waters of Quaternary aquiferous horizon. Slightly better protected are waters of Opillia and Tyras aquiferous horizons of Badenian located at the bottom under Kosiv clay layers. Most protected are urgent waters of Cretaceous horizon placed under Quarternary layer and Miocene sediments. Key words: ground waters, protectiveness, vulnerability, pollution, aeration zones.
23
Isaias, José Claudio, Edson de Oliveira Pamplona e José Henrique de Freitas Gomes. "Model to Estimate Monthly Time Horizons for Application of DEA in Selection of Stock Portfolio and for Maintenance of the Selected Portfolio". Mathematical Problems in Engineering 2015 (2015): 1–14. http://dx.doi.org/10.1155/2015/957893.
Testo completoAbstract (sommario):
In the selecting of stock portfolios, one type of analysis that has shown good results is Data Envelopment Analysis (DEA). It, however, has been shown to have gaps regarding its estimates of monthly time horizons of data collection for the selection of stock portfolios and of monthly time horizons for the maintenance of a selected portfolio. To better estimate these horizons, this study proposes a model of mathematical programming binary of minimization of square errors. This model is the paper’s main contribution. The model’s results are validated by simulating the estimated annual return indexes of a portfolio that uses both horizons estimated and of other portfolios that do not use these horizons. The simulation shows that portfolios with both horizons estimated have higher indexes, on average 6.99% per year. The hypothesis tests confirm the statistically significant superiority of the results of the proposed mathematical model’s indexes. The model’s indexes are also compared with portfolios that use just one of the horizons estimated; here the indexes of the dual-horizon portfolios outperform the single-horizon portfolios, though with a decrease in percentage of statistically significant superiority.
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Liu, Zhining, Chengyun Song, Kunhong Li, Bin She, Xingmiao Yao, Feng Qian e Guangmin Hu. "Horizon extraction using ordered clustering on a directed and colored graph". Interpretation 8, n. 1 (1 febbraio 2020): T1—T11. http://dx.doi.org/10.1190/int-2018-0161.1.
Testo completoAbstract (sommario):
Extracting horizons from a seismic image has been playing an important role in seismic interpretation. However, how to fully use global-level information contained in the seismic images such as the order of horizon sequences is not well-studied in existing works. To address this issue, we have developed a novel method based on a directed and colored graph, which encodes effective context information for horizon extraction. Following the commonly used framework, which generates horizon patches and then groups them into horizons, we first build a directed and colored graph by representing horizon patches as vertices. In addition, edges in the graph encode the relative spatial positions of horizon patches. This graph explicitly captures the geologic context, which guides the grouping of the horizon patches. Then, we conduct premerging to group horizon patches through matching some predefined subgraph patterns that are designed to capture some special spatial distributions of horizon patches. Finally, we have developed an ordered clustering method to group the rest of the horizon patches into horizons based on the pairwise similarities of horizon patches while preserving geologic reasonability. Experiments on real seismic data indicate that our method can outperform the autotracking approach solely based on the similarity of local waveforms and can correctly pick the horizons even across the fault without any crossing, which demonstrates the effectiveness of exploring the spatial information, i.e., the order of horizon sequences and special spatial distribution of horizon patches.
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Webb, T. H. "Identification of functional horizons to predict physical properties for soils from alluvium in Canterbury, New Zealand". Soil Research 41, n. 5 (2003): 1005. http://dx.doi.org/10.1071/sr01077.
Testo completoAbstract (sommario):
Lack of soil physical data, particularly soil water release data and hydraulic conductivity data, is recognised as one of the greatest limitations to the widespread application of simulation models, needed to address environmental issues. Because of the expense of generating new soil physical data pedotransfer functions may be used to predict soil physical data from existing information, notably soil morphology. Pedological horizon descriptions can then be used to estimate soil physical properties for many points in the landscape. The soils used in this study were derived from a systematic sampling of soil profiles for soil physical characteristics for 8 soils series within 2 drainage sequences on the post-glacial and glacial surfaces of the Canterbury Plains. Soil series in each sequence varied from shallow sandy loam, well-drained soils to deep clay loam, poorly drained soils. Each soil series was represented by 9 profiles. Three horizons in each soil profile were sampled for soil porosity values, particle size, and saturated- and near-saturated hydraulic conductivity. Pedological horizons were grouped into functional horizons on the basis of soil morphologic attributes expected to have closest relationships with soil physical properties (ped size, ped type, packing class, consistence and presence of argillic horizons). For topsoils, functional horizons based on ped size were found to have greatest predictive ability and provided separation between horizons for bulk density, macroporosity, clay content, wilting point, readily available water, and near-saturated hydraulic conductivity. For subsoils, horizons with clay content >35% had distinct relationships with soil physical properties and needed to be separated from other subsoil horizons. For the remaining horizons, separations in soil water release characteristics and some hydraulic conductivity data were obtained by functional horizons based on packing class and the presence of argillic horizons. Adding ped size to the functional horizon definition provided further separation of horizons for hydraulic conductivity. This study demonstrates that a range of pedological horizons, derived from a wide range of soil types, can be grouped into 4 functional topsoil horizons and 3–5 functional subsoil horizons on the basis of simple morphological attributes or merged pedological horizons. The functional horizons, thus created, enable statistical distributions of soil water release and hydraulic conductivity data to be predicted for map units.
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Gogia, Rahul, Raman Singh, Paul de Groot, Harshit Gupta, Seshan Srirangarajan, Jyoti Phirani e Sayan Ranu. "Tracking 3D seismic horizons with a new hybrid tracking algorithm". Interpretation 8, n. 4 (14 settembre 2020): SQ39—SQ45. http://dx.doi.org/10.1190/int-2019-0296.1.
Testo completoAbstract (sommario):
We have developed a new algorithm for tracking 3D seismic horizons. The algorithm combines an inversion-based, seismic-dip flattening technique with conventional, similarity-based autotracking. The inversion part of the algorithm aims to minimize the error between horizon dips and computed seismic dips. After each cycle in the inversion loop, more seeds are added to the horizon by the similarity-based autotracker. In the example data set, the algorithm is first used to quickly track a set of framework horizons, each guided by a small set of user-picked seed positions. Next, the intervals bounded by the framework horizons are infilled to generate a dense set of horizons, also known as HorizonCube. This is done under the supervision of a human interpreter in a similar manner. The results show that the algorithm behaves better than unconstrained flattening techniques in intervals with trackable events. Inversion-based algorithms generate continuous horizons with no holes to be filled posttracking with a gridding algorithm and no loop skips (jumping to the wrong event) that need to be edited as is standard practice with autotrackers. Because editing is a time-consuming process, creating horizons with inversion-based algorithms tends to be faster than conventional autotracking. Horizons created with the adopted algorithm follow seismic events more closely than horizons generated with the inversion-only algorithm, and the fault crossings are sharper.
27
Bhattacharyya, Jishnu, e David Mattingly. "Universal horizons in maximally symmetric spaces". International Journal of Modern Physics D 23, n. 13 (novembre 2014): 1443005. http://dx.doi.org/10.1142/s0218271814430056.
Testo completoAbstract (sommario):
Universal horizons in Hořava–Lifshitz gravity and Einstein-æther theory are the equivalent of causal horizons in general relativity and appear to have many of the same properties, including a first law of horizon thermodynamics and thermal radiation. Since universal horizons are infrared (IR) solutions of a putative power counting renormalizable quantum gravitational theory, fully understanding their thermodynamics will shed light on the interplay between black hole thermodynamics and quantum gravity. In this paper, we provide a complete classification, including asymptotic charges, of all four-dimensional static and spherically symmetric universal horizon solutions with maximally symmetric asymptotics — the equivalents of the Schwarzschild, Schwarzschild–de Sitter or Schwarzschild–anti-de Sitter spacetimes. Additionally, we derive the associated first laws for the universal horizon solutions. Finally, we prove that independent of asymptotic boundary conditions, any spherically symmetric solution in Hořava–Lifshitz gravity with a universal horizon is also a solution of Einstein-æther theory, thereby broadening and complementing the known equivalence region of the solution spaces.
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Donald, Richard G., Darwin W. Anderson e John W. B. Stewart. "The distribution of selected soil properties in relation to landscape morphology in forested Gray Luvisol soils". Canadian Journal of Soil Science 73, n. 2 (1 maggio 1993): 165–72. http://dx.doi.org/10.4141/cjss93-019.
Testo completoAbstract (sommario):
Properties of Gray Luvisol soils were examined in relation to landscape position in a boreal setting in Saskatchewan. The thickness of the organic, Ae and Bt horizons, the pH of the Ae, depth to carbonates and the percent clay in the Bt horizon were determined on samples taken from 80 profiles on a 70 × 56-m grid. At each sample location the landform element was described as one of eight elements based on the gradient, profile curvature and plan curvature. The results show that the distribution of soil properties varied as a function of landscape morphology and moisture regime. In general, the pH of the Ae horizons was higher, and the thickness of Ae and organic horizons were greater in convergent areas. In lower footslope soils, a shallow carbonate-rich water table led to a moderately alkaline pH in the Ae horizons and restricted profile development, presumably due to restricted vertical leaching. The ratio of Ae to Bt horizon thickness was greatest on upper slopes, decreasing in lower footslope soils and in convergent areas. The Bt horizons of lower footslope soils contained more clay than Bt horizons of upper slope soils, possibly as the result of the lateral redistribution of soluble and suspended constituents from divergent to convergent areas of the landscape. Keywords: Geomorphology, Luvisol, horizon development, soil depth, soil pH, illuviation
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Chakrabarty, Anindya, Rameshwar Dubey e Anupam De. "An innovative approach to mitigating horizon mismatch". International Journal of Innovation Science 8, n. 2 (6 giugno 2016): 161–80. http://dx.doi.org/10.1108/ijis-06-2016-011.
Testo completoAbstract (sommario):
Purpose This paper aims to propose an innovative approach to risk measurement for the abolition of selection bias arising from the specious selection of different horizons for investment and risk computation of equity-linked-saving schemes (ELSS). Design/methodology/approach ELSS has a lock-in period of three years, but shorter horizons’ (daily/weekly/monthly) return data are preferred, in practice, for risk computation. This results in horizon mismatch. This paper studies the consequences of this mismatch and provides a noble solution to diminish its effect on investors’ decision-making. To accomplish this objective, the paper uses an innovative methodology, maximal overlap discrete wavelet transformation, to segregate the price movements across different horizons. Risk across all horizons is measured using Cornish-Fisher expected shortfall and Cornish-Fisher value-at-risk methods. Findings The degree of consistency of risk-based rankings across horizons is examined by means of the Spearman and Kendall’s rank correlation tests. The risk-based ranking of ELSS is found to vary significantly with the change in investor’s horizon. Precisely, the rankings formulated using daily net asset values are significantly different from the rankings developed using fluctuations over longer horizons (two-four and four-eight years). Originality/value This finding indicates that the ranking exercise may mislead investors if horizon correction is not done while developing such rankings.
30
Wright, Joseph. "To Invest or Insure?" Comparative Political Studies 41, n. 7 (13 febbraio 2008): 971–1000. http://dx.doi.org/10.1177/0010414007308538.
Testo completoAbstract (sommario):
In this article, the author argues that the time horizon a dictator faces affects his incentives over the use of aid in three ways. First, dictators have a greater incentive to invest in public goods when they have a long time horizon. Second, dictators with short time horizons often face the threat of challengers to the regime; this leads them to forgo investment and instead consume state resources in two forms that harm growth: repression and private pay-offs to political opponents. Third, dictators with short time horizons have a strong incentive to secure personal wealth as a form of insurance in case the regime falls. Using panel data on dictatorships in 71 developing countries from 1961 to 2001, the author finds that time horizons have a positive impact on aid effectiveness: Foreign aid is associated with positive growth when dictators face long time horizons and negative growth when time horizons are short.
31
Will, Christiane, Andrea Th�rmer, Antje Wollherr, Heiko Nacke, Nadine Herold, Marion Schrumpf, Jessica Gutknecht, Tesfaye Wubet, Fran�ois Buscot e Rolf Daniel. "Horizon-Specific Bacterial Community Composition of German Grassland Soils, as Revealed by Pyrosequencing-Based Analysis of 16S rRNA Genes". Applied and Environmental Microbiology 76, n. 20 (20 agosto 2010): 6751–59. http://dx.doi.org/10.1128/aem.01063-10.
Testo completoAbstract (sommario):
ABSTRACT The diversity of bacteria in soil is enormous, and soil bacterial communities can vary greatly in structure. Here, we employed a pyrosequencing-based analysis of the V2-V3 16S rRNA gene region to characterize the overall and horizon-specific (A and B horizons) bacterial community compositions in nine grassland soils, which covered three different land use types. The entire data set comprised 752,838 sequences, 600,544 of which could be classified below the domain level. The average number of sequences per horizon was 41,824. The dominant taxonomic groups present in all samples and horizons were the Acidobacteria, Betaproteobacteria, Actinobacteria, Gammaproteobacteria, Alphaproteobacteria, Deltaproteobacteria, Chloroflexi, Firmicutes, and Bacteroidetes. Despite these overarching dominant taxa, the abundance, diversity, and composition of bacterial communities were horizon specific. In almost all cases, the estimated bacterial diversity (H′) was higher in the A horizons than in the corresponding B horizons. In addition, the H′ was positively correlated with the organic carbon content, the total nitrogen content, and the C-to-N ratio, which decreased with soil depth. It appeared that lower land use intensity results in higher bacterial diversity. The majority of sequences affiliated with the Actinobacteria, Bacteroidetes, Cyanobacteria, Fibrobacteres, Firmicutes, Spirochaetes, Verrucomicrobia, Alphaproteobacteria, Betaproteobacteria, and Gammaproteobacteria were derived from A horizons, whereas the majority of the sequences related to Acidobacteria, Chloroflexi, Gemmatimonadetes, Nitrospira, TM7, and WS3 originated from B horizons. The distribution of some bacterial phylogenetic groups and subgroups in the different horizons correlated with soil properties such as organic carbon content, total nitrogen content, or microbial biomass.
32
Ewing, Blake. "Koselleck’s Historik and the Horizons of Politics". Contributions to the History of Concepts 13, n. 2 (1 dicembre 2018): 79–99. http://dx.doi.org/10.3167/choc.2018.130204.
Testo completoAbstract (sommario):
Political theorists, especially in the subfield of ideology studies, continue to draw insights from Begriffsgeschichte (conceptual history) to help them better analyze the morphology of political concepts over time. However, other aspects of Reinhart Koselleck’s work remain underutilized. This is especially true of the connections between Begriffsgeschichte and his development of a theory of history (Historik), dealing with the broader intersection of language, structure, and the experience of time. This article focuses on just one aspect of this intersection: on the potential relevance of Koselleck’s use of the concept of horizon to theorize a particular “horizonal mode” of the politics of time. After discussing some relevant features of the horizon metaphor, the article moves to reappraise Koselleck’s use of the concept before elaborating and expanding on it to claim that Koselleck helps to showcase the contestation of different temporal horizons as a core feature of political thinking.
33
Mamahit, Ferry Y. "Hermeneutika Peleburan Dua Horizon Anthony Thiselton dan Tantangan dari Antropologi Lintas Budaya". Veritas : Jurnal Teologi dan Pelayanan 18, n. 1 (20 settembre 2019): 33–46. http://dx.doi.org/10.36421/veritas.v18i1.320.
Testo completoAbstract (sommario):
Masalah klasik dalam hermeneutika alkitabiah adalah bagaimana menjembatani kesenjangan antara teks Alkitab yang berkonteks budaya kuno dan pembacanya yang berkonteks budaya modern. Salah satu pendekatan yang diajukan untuk mengatasi persoalan tersebut adalah model peleburan horizon-horizon (the fusions of horizons), yang kemudian dikembangkan oleh Anthony Thiselton dengan peleburan dua horizonnya (the fusions of two horizons). Meski pendekatan hermeneutis yang dilakukan oleh Thiselton sangat komprehensif dan serius dalam menjembatani kesenjangan ini, pendekatan konteks berkultur tunggalnya (baca: budaya Barat) ini belum dapat menjawab tantangan dari antropologi lintas-budaya, khususnya kompleksitas konteks budaya pembaca modern yang berkarakter beragam, berlapis dan bersilang. Jadi, pendekatan ini perlu mempertimbangkan pendekatan hermeneutis yang lebih sensitif terhadap kompleksitas tersebut sebagai tambahan atau pelengkap pendekatan peleburan horizon-horizon (addenda hermeneutica).
Kata-kata Kunci: Anthony Thiselton, hermeneutika alkitabiah, peleburan-peleburan horizon, kompleksitas konteks budaya, hermeneutika kontekstual
English : The classic problem in biblical hermeneutics is how to bridge the gap between the ancient cultural context of the biblical texts and the modern cultural context of the reader. One of the approaches proposed to deal with this issue is the model of the fusion of horizons that is later on developed by Anthony Thiselton with his fusions of two horizons. Albeit comprehensive and severe in bridging the gap, his mono-cultural (Western) approach to the context has not yet answered the challenge from cross-cultural anthropology, especially the complexity of the culture of the modern reader characterized by varied, multi-layered and cross-culturally. The approach thus needs to consider a hermeneutical approach that is more sensitive to that complexity as addition into or compliment to the fusions of horizons approach (addenda hermeneutica).
Keywords: Anthony Thiselton, biblical hermeneutics, the fusions of horizons, the complexity of cultural context, contextual hermeneutics
34
Huang, Jing, Xia-Fang Sheng, Jun Xi, Lin-Yan He, Zhi Huang, Qi Wang e Zhen-Dong Zhang. "Depth-Related Changes in Community Structure of Culturable Mineral Weathering Bacteria and in Weathering Patterns Caused by Them along Two Contrasting Soil Profiles". Applied and Environmental Microbiology 80, n. 1 (27 settembre 2013): 29–42. http://dx.doi.org/10.1128/aem.02335-13.
Testo completoAbstract (sommario):
ABSTRACTBacteria play important roles in mineral weathering and soil formation. However, few reports of mineral weathering bacteria inhabiting subsurfaces of soil profiles have been published, raising the question of whether the subsurface weathering bacteria are fundamentally distinct from those in surface communities. To address this question, we isolated and characterized mineral weathering bacteria from two contrasting soil profiles with respect to their role in the weathering pattern evolution, their place in the community structure, and their depth-related changes in these two soil profiles. The effectiveness and pattern of bacterial mineral weathering were different in the two profiles and among the horizons within the respective profiles. The abundance of highly effective mineral weathering bacteria in the Changshu profile was significantly greater in the deepest horizon than in the upper horizons, whereas in the Yanting profile it was significantly greater in the upper horizons than in the deeper horizons. Most of the mineral weathering bacteria from the upper horizons of the Changshu profile and from the deeper horizons of the Yanting profile significantly acidified the culture media in the mineral weathering process. The proportion of siderophore-producing bacteria in the Changshu profile was similar in all horizons except in the Bg2 horizon, whereas the proportion of siderophore-producing bacteria in the Yanting profile was higher in the upper horizons than in the deeper horizons. Both profiles existed in different highly depth-specific culturable mineral weathering community structures. The depth-related changes in culturable weathering communities were primarily attributable to minor bacterial groups rather than to a change in the major population structure.
35
Yang, Run-Qiu, Rong-Gen Cai e Li Li. "Constraining the number of horizons with energy conditions". Classical and Quantum Gravity 39, n. 3 (4 gennaio 2022): 035005. http://dx.doi.org/10.1088/1361-6382/ac4118.
Testo completoAbstract (sommario):
Abstract We show that the number of horizons of static black holes can be strongly constrained by energy conditions of matter fields. After a careful clarification on the ‘interior’ of a black hole, we prove that if the interior of a static black hole satisfies strong energy condition or null energy condition, there is at most one non-degenerated inner Killing horizon behind the non-degenerated event horizon. Our result offers some universal restrictions on the number of horizons. Interestingly and importantly, it also suggests that matter not only promotes the formation of event horizon but also prevents the appearance of multiple horizons inside black holes. Furthermore, using the geometrical construction, we obtain a radially conserved quantity which is valid for general static spacetimes.
36
STRONG, W. L., e G. H. LA ROI. "USE OF SOIL HORIZONS AS ECOLOGICAL SAMPLING UNITS". Canadian Journal of Soil Science 68, n. 1 (1 febbraio 1988): 151–55. http://dx.doi.org/10.4141/cjss88-014.
Testo completoAbstract (sommario):
Extractable nutrients and physical properties of Eutric Brunisols from pine and aspen stands were evaluated for their relationship to soil horizons classified according to morphological criteria. The results indicate strong horizon-nutrient associations, suggesting that soil horizons are appropriate sampling units for ecological studies concerned with below-ground nutrient and edaphic conditions. Key words: Nutrients, principal components analysis, soil horizon
37
Melo, Diego Vandeval Maranhão de, Brivaldo Gomes de Almeida, Edivan Rodrigues de Souza, Laércio Santos Silva e Paulo Klinger Tito Jacomine. "Structural quality of polyacrylamide-treated cohesive soils in the coastal tablelands of Pernambuco". Revista Brasileira de Ciência do Solo 38, n. 2 (aprile 2014): 476–85. http://dx.doi.org/10.1590/s0100-06832014000200012.
Testo completoAbstract (sommario):
Water-soluble polymers are characterized as effective flocculating agents due to their molecular features. Their application to soils with horizons with structural problems, e.g, a cohesive character, contributes to improvements in the physical quality and thus to the agricultural suitability of such soils. The purpose of this study was to evaluate the structural quality of soils with cohesive horizons of coastal tablelands in the State of Pernambuco treated with polyacrylamide (PAM) as chemical soil conditioner. To this end, three horizons (one cohesive and two non-cohesive) of a Yellow Argisol (Ultisol) were evaluated and to compare cohesive horizons, the horizon of a Yellow Latosol (Oxisol) was selected. The treatments consisted of aqueous PAM solutions (12.5; 50.0; 100.0 mg kg-1) and distilled water (control). The structural aspects of the horizons were evaluated by the stability (soil mass retained in five diameter classes), aggregate distribution per size class (mean weight diameter- MWD, geometric mean diameter - GMD) and the magnitude of the changes introduced by PAM by measuring the sensitivity index (Si). Aqueous PAM solutions increased aggregate stability in the largest evaluated diameter class of the cohesive and non-cohesive horizons, resulting in higher MWD and GMD, with highest efficiency of the 100 mg kg-1 solution. The cohesive horizon Bt1 in the Ultisol was most sensitive to the action of PAM, where highest Si values were found, but the structural quality of the BA horizon of the Oxisol was better in terms of stability and aggregate size distribution.
38
Jiménez Martínez, Arturo, Ma del Carmen Gutierrez Castorena, Edgar Vladimir Gutiérrez Castorena, Alejandro Alarcón, Mayra Elena Gavito Pardo e Noé Manuel Montaño Árias. "El papel de los hongos en la conservación de Andosols: estudio de caso en Tlaxcala, México". REVISTA TERRA LATINOAMERICANA 37, n. 2 (15 aprile 2019): 93. http://dx.doi.org/10.28940/terra.v37i2.437.
Testo completoAbstract (sommario):
Tlaxcala state, Mexico, show environmental problems related to soil erosion; however, in some areas of Andosols, with pine forests and even in agricultural areas, it has been observed that their degradation is minimal. The abundant presence of mycelium even in subsurface horizons can be the reason why soils are conserved. The objectives of this study were to characterize the edaphic properties in different geo-morphological positions, to identify the species of arbuscular mycorrhizal fungi (AMF) and to determine the relationship of the mycelium with aggregates and elementary particles in a Vitric Andosols of Calpulalpan, Tlaxcala, Mexico. The results showed that soils have different sequences and thicknesses of ashes and lapillis pomaceous and have moderate to high fertility. The crumbly structure dominated in upper horizons and simple granular in sub-horizons. The horizons showed high retention of humidity and permeability facilitating mycelial development and formation of AMF spores up to 120 cm deep. Ten species of AMF were recorded and the most abundant was Funneliformis mosseae. The micro-morphological analysis showed different relationships between the mycelium, horizon and soil particles, with organic waste (horizon O), with macro and micro aggregates (horizons A and B), with allophane and imogolite (horizons B) and lapillis (horizon C). The fungal mycelium forms networks throughout the soil, and in the lapillis it inserts the pumice particles (like a rosary) through the tubular vesicular pores, which provides stability to the Andosols and prevents their degradation.
39
Kamara, Avraham, Robert A. Korajczyk, Xiaoxia Lou e Ronnie Sadka. "Horizon Pricing". Journal of Financial and Quantitative Analysis 51, n. 6 (dicembre 2016): 1769–93. http://dx.doi.org/10.1017/s0022109016000685.
Testo completoAbstract (sommario):
The literature documents heterogeneity in the delay of stock price reaction to systematic shocks, implying that asset risk depends on investment horizon. We study the pricing of risk factors across investment horizons. Value (liquidity) risk is priced over intermediate (short) horizons. Conditioning horizon-factor exposures on firm characteristics indicates that characteristics, with the exception of momentum, are not priced beyond their contribution to systematic risk. Long-horizon institutional investors overweight assets with high intermediate-horizon exposures to value risk and high short-horizon exposures to liquidity risk. The results highlight the importance of investment horizon in determining risk premia.
40
Travassos, Jandyr M., Saulo S. Martins, Jefferson C. Simões e Webe J. Mansur. "RADAR DIFFRACTION HORIZONS IN SNOW AND FIRN DUE TO A SURFICIAL VERTICAL TRANSFER OF MASS". Revista Brasileira de Geofísica 36, n. 4 (21 dicembre 2018): 1. http://dx.doi.org/10.22564/rbgf.v36i4.1978.
Testo completoAbstract (sommario):
ABSTRACT. We focus here on three horizons conspicuously embedded in the rich radar stratigraphy revealed on the fixed-offset radar data obtained Plateau Detroit, Antarctic Peninsula. Spatial filtering removed the more energetic reflection field and the surface wave arrivals at the earlier time, leaving only the diffracted field. This is particularly striking for the early time horizon where the direct wave arrivals had shrouded the diffractions before filtering. The density estimates and the photographic datasets from a centrally located well at depths compatible with the diffraction horizons suggested they share a common origin: a vertical transfer of mass associated with the formation of surficial hoar from a strong vertical temperature gradient in the snow cover, followed by a quick burial by fresh snow in a high accumulation environment. We have inverted the fundamental mode of the phase velocity dispersion of the surface waves to obtain a group velocity estimate and its depth range, used to improve the 1–D velocity model from a CMP gather by correcting its first velocity estimate. The same inversion solved an apparent ambiguity in our data by associating the surficial horizon with a specific density residual. We have also shown through modeling that the diffraction horizons seen in our data can be explained by the existence of large coarse–grained faceted crystals which became denser with depth than the surrounding firn.Keywords: GPR, radar, campo difratado, modelo de velocidade, guia de ondas, estratigrafia polar, depth hoar, AntárticaRESUMO. Concentramo-nos aqui em três horizontes conspicuamente embutidos na rica estratigrafia revelada nos dados de radar de afastamento constante obtidos Platô Detroit, Península Antártica. Uma filtragem espacial removeu o campo de reflexão mais energético e as chegadas de onda de superfície das primeiras chegadas, deixando apenas o campo difratado. Isso é notável para o horizonte de primeiras chegadas, onde as ondas diretas encobriam as difrações antes da filtragem. As estimativas de densidade e os conjuntos de dados fotográficos do poço localizado no centro da aquisição mostra em profundidades cristais compatíveis com os horizontes de difração dos dados de GPR sugerindo uma origem comum: uma transferência vertical de massa associada à formação de hoar devido a um forte gradiente vertical de temperatura na cobertura de neve fresca em um ambiente de alta acumulação. Nós invertemos o modo fundamental da dispersão de velocidade de fase das ondas de superfície para obter uma estimativa de velocidade de grupo e sua faixa de profundidade usada para melhorar o modelo de velocidade 1-D a partir de um CMP, corrigindo sua primeira estimativa de velocidade. A mesma inversão resolveu uma ambiguidade aparente em nossos dados ao associar o horizonte superficial a uma densidade específica residual. Também mostramos através de modelagem que os horizontes de difração observados em nossos dados podem ser explicados pela existência de grandes cristais facetados de granulação grossa que se tornaram mais densos com a profundidade do que o firn circundante.Palavras-chave: GPR, radar, campo de difração, modelo de velocidade, guia de onda, estratigrafia polar, depth hoar, Antarctica
41
Wu, Hao, Bo Zhang, Tengfei Lin, Danping Cao e Yihuai Lou. "Semiautomated seismic horizon interpretation using the encoder-decoder convolutional neural network". GEOPHYSICS 84, n. 6 (1 novembre 2019): B403—B417. http://dx.doi.org/10.1190/geo2018-0672.1.
Testo completoAbstract (sommario):
The seismic horizon is a critical input for the structure and stratigraphy modeling of reservoirs. It is extremely hard to automatically obtain an accurate horizon interpretation for seismic data in which the lateral continuity of reflections is interrupted by faults and unconformities. The process of seismic horizon interpretation can be viewed as segmenting the seismic traces into different parts and each part is a unique object. Thus, we have considered the horizon interpretation as an object detection problem. We use the encoder-decoder convolutional neural network (CNN) to detect the “objects” contained in the seismic traces. The boundary of the objects is regarded as the horizons. The training data are the seismic traces located on a user-defined coarse grid. We give a unique training label to the time window of seismic traces bounded by two manually picked horizons. To efficiently learn the waveform pattern that is bounded by two adjacent horizons, we use variable sizes for the convolution filters, which is different than current CNN-based image segmentation methods. Two field data examples demonstrate that our method is capable of producing accurate horizons across the fault surface and near the unconformity which is beyond the current capability of horizon picking method.
42
Forte, Emanuele, Matteo Dossi, Michele Pipan e Anna Del Ben. "Automated phase attribute-based picking applied to reflection seismics". GEOPHYSICS 81, n. 2 (1 marzo 2016): V141—V150. http://dx.doi.org/10.1190/geo2015-0333.1.
Testo completoAbstract (sommario):
We have applied an attribute-based autopicking algorithm to reflection seismics with the aim of reducing the influence of the user’s subjectivity on the picking results and making the interpretation faster with respect to manual and semiautomated techniques. Our picking procedure uses the cosine of the instantaneous phase to automatically detect and mark as a horizon any recorded event characterized by lateral phase continuity. A patching procedure, which exploits horizon parallelism, can be used to connect consecutive horizons marking the same event but separated by noise-related gaps. The picking process marks all coherent events regardless of their reflection strength; therefore, a large number of independent horizons can be constructed. To facilitate interpretation, horizons marking different phases of the same reflection can be automatically grouped together and specific horizons from each reflection can be selected using different possible methods. In the phase method, the algorithm reconstructs the reflected wavelets by averaging the cosine of the instantaneous phase along each horizon. The resulting wavelets are then locally analyzed and confronted through crosscorrelation, allowing the recognition and selection of specific reflection phases. In case the reflected wavelets cannot be recovered due to shape-altering processing or a low signal-to-noise ratio, the energy method uses the reflection strength to group together subparallel horizons within the same energy package and to select those satisfying either energy or arrival time criteria. These methods can be applied automatically to all the picked horizons or to horizons individually selected by the interpreter for specific analysis. We show examples of application to 2D reflection seismic data sets in complex geologic and stratigraphic conditions, critically reviewing the performance of the whole process.
43
Braun, Barbara. "Colluvic Umbrisols As a Result of the Erosion Process of Rolling and Hilly Country in Agricultural Area". Miscellanea Geographica 14, n. 1 (1 dicembre 2010): 213–19. http://dx.doi.org/10.2478/mgrsd-2010-0020.
Testo completoAbstract (sommario):
Abstract Agricultural activity, especially agricultural mechanization, leads to acceleration of erosion in rolling and hilly country. The level of the erosion process, already during territorial observations, may be assessed by the thickness of the humus horizon. In the vicinity of Bytów, the deluvial humus horizons have even achieved thickness of 100 cm. These horizons are also richer in organic matter than humus horizons located on flat-topped mountains and mountain sides. Deluvial horizons are characterized by a somewhat less acid reaction, sometimes even neutral, and somewhat greater dehydration of the sorption complex by alkaline cations.
44
Wu, Xinming, e Sergey Fomel. "Least-squares horizons with local slopes and multigrid correlations". GEOPHYSICS 83, n. 4 (1 luglio 2018): IM29—IM40. http://dx.doi.org/10.1190/geo2017-0830.1.
Testo completoAbstract (sommario):
Most seismic horizon extraction methods are based on seismic local reflection slopes that locally follow seismic structural features. However, these methods often fail to correctly track horizons across discontinuities such as faults and noise because the local slopes can only correctly follow laterally continuous reflections. In addition, seismic amplitude or phase information is not used in these methods to compute horizons that follow a consistent phase (e.g., peaks or troughs). To solve these problems, we have developed a novel method to compute horizons that globally fit the local slopes and multigrid correlations of seismic traces. In this method, we first estimate local reflection slopes by using structure tensors and compute laterally multigrid slopes by using dynamic time warping (DTW) to correlate seismic traces within multiple laterally coarse grids. These coarse-grid slopes can correctly correlate reflections that may be significantly dislocated by faults or other discontinuous structures. Then, we compute a horizon by fitting, in the least-squares sense, the slopes of the horizon with the local reflection slopes and multigrid slopes or correlations computed by DTW. In this least-squares system, the local slopes on the fine grid and the multiple coarse-grid slopes will fit a consistent horizon in areas without lateral discontinuities. Across laterally discontinuous areas where the local slopes fail to correctly correlate reflections and mislead the horizon extraction, the coarse-grid slopes will help to find the corresponding reflections and correct the horizon extraction. In addition, the multigrid correlations or slopes computed by dynamic warping can also assist in computing phase-consistent horizons. We apply the proposed horizon extraction method to multiple 2D and 3D examples and obtain accurate horizons that follow consistent phases and correctly track reflections across faults.
45
Onweremadu, Emmanuel, Bernadine Aririguzo, Nnaemeka Okoli e Isaiah Afangide. "Temporal Variability of Soil Reaction Among Surface and Near-Surface Horizons of Soils of Dissimilar Lithology in a Humid Tropical Environment". International Journal of Environment 10, n. 1 (23 luglio 2021): 99–111. http://dx.doi.org/10.3126/ije.v10i1.38532.
Testo completoAbstract (sommario):
The study investigated changes in soil reaction among surface and near surface horizons of four soil groups as affected by wet and dry seasons in Southeastern Nigeria. A geological map of the area guided soil sampling. Free survey approach was used in locating soil profiles. Soil samples were collected based on horizon differentiation and samples were collected from the AB-horizon (near-surface) and the A-horizon (Surface). Routine laboratory analyses were conducted on these soil samples after sieving through a 2-mm sieve. Data were subjected to analysis of variance (ANOVA) using SAS Statistical Computer Package. There were significant (p<0.05) changes in soil reaction in A- and AB-horizons in the dry seasons of 2016 and 2017. Similarly, in the wet season, soil pH varied significantly (p<0.05) in 2016 and 2017. Soil reaction significantly (p<0.05) differed in AB-horizons in both 2016 and 2017 irrespective of the season. All soil samples were acidic irrespective of lithologic material and season with pH values ranging from 4.20-5.60 and 3.31-5.42 in the A- and AB-horizons, respectively.
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Bouda, S., e K. P. Isaac. "Influence of soil redox conditions on oxidation of biotite". Clay Minerals 21, n. 2 (giugno 1986): 149–57. http://dx.doi.org/10.1180/claymin.1986.021.2.04.
Testo completoAbstract (sommario):
AbstractBiotites from three peaty gleyed podzol soil profiles on ranite bedrock were examined to investigate the oxidation of the octahedral Fe during weathering. Oxidation of these biotites as determined by Mössbauer spectroscopy shows a good correlation with the in situ measured soil Eh values of the sampled horizons. In every soil profile the highest Eh measured is in the A horizon and the lowest in the C horizon. Similarly, biotites from the A horizons are the most oxidized compared with those from the lower horizons. In most of the samples the oxidation is accompanied by loss of K+ from the lattice, as demonstrated by a moderate degree of vermiculitization.
47
Glina, Bartłomiej, Jarosław Waroszewski e Cezary Kabała. "Water retention of the loess-derived Luvisols with lamellic illuvial horizon in the Trzebnica Hills (SW Poland)". Soil Science Annual 65, n. 1 (1 marzo 2014): 18–24. http://dx.doi.org/10.2478/ssa-2014-0003.
Testo completoAbstract (sommario):
Abstract The aim of work was to characterize the water retention in the silt-textured Luvisols with lamellic illuvial horizon (argic) that occur in the loess covered northern part of the Silesian Lowland. Soil pits were localized on the Trzebnica Hills near the villages: Machnice (profile 1), Skarszyn (profile 2) and Zaprężyn (profile 3 and 4). Profiles Machnice 1 and Skarszyn 2 were situated in the upper parts of the hills covered with beech stands with an admixture of oak, linden and maple. Profiles Zaprężyn 3 and 4 were situated in the central and lower parts of the arable slope. During the field work conducted in April 2011, 29 soil samples were collected for texture, bulk density and water properties analysis. The soils under study were characterized by texture of silt loam with lower clay content in humus horizons (.loamy silt. according to Polish classification), and higher clay content (.clayey silt.) in the illuvial and subsoil horizons. The texture of all examined profiles was dominated by the „loess“ fractions. Variable abundance of the massive lamellae causes variations in water properties of the illuvial (sub-)horizons. It was found that lamellic illuvial horizons in the loess-derived Luvisols have higher field water capacity than the homogenous illuvial horizons, apart of the clay content. There was no apparent effect of the horizon kind (homogeneous versus lamellic) on the soil bulk density. These properties mainly depended on the total clay content in a particular horizon (sub-horizon).
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Giang, Nguyen Thi, Ngo Thi Dung e Nguyen Van Dung. "Modeling of Infiltration Characteristics by the Modified Kostiakov Method: A Case Study in Thuong River Alluvial Soil in Vietnam". Vietnam Journal of Agricultural Sciences 2, n. 3 (24 dicembre 2019): 418–25. http://dx.doi.org/10.31817/10.31817/vjas.2019.2.3.02.
Testo completoAbstract (sommario):
The purpose of this study was to apply the modified Kostiakov method to determine the soil infiltration rate and permeated water amount of Thuong River alluvial soil for orange plantations in Lang Giang district, Bac Giang province, Vietnam. The soil particle size ranged from 0.02 to 2.00mm mainly found in the surface horizon (>77.7%). The soil was slightly acidic in the surface horizon, and highly acidic in the subsurface horizons (pHKCl from 3.42 to 4.79). The organic matter content of the surface horizon was mederate, while it was very low in the other horizons. The total nitrogen (N) content was low (0.15%) in the surface horizon and very low in the subsurface horizons (0.02-0.06%) while the available N was medium. The total phosphorus (P) content in the surface horizon was high (0.4%) and medium in the other horizons. Available P in the surface horizon was high (18.6mg per 100g soil) and decreased in lower depths to only 0.3mg per 100g soil in the deepest (5th) horizon. The total and available potassium measurements were very low. A filtration characteristic model was developed by using the modified Kostiakov method for alluvial soil. The constant values a, a, and b of the equation y = ata + b were 0.8035, 0.758, and 0.00346, respectively, which were smaller than 1. The average percentage difference between the actual and calculated values by the model was only 0.141%, indicating that the calculated values can accurately predict the actual data measurements in the field.
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Giang, Nguyen Thi, Ngo Thi Dung e Nguyen Van Dung. "Modeling of Infiltration Characteristics by the Modified Kostiakov Method: A Case Study in Thuong River Alluvial Soil in Vietnam". Vietnam Journal of Agricultural Sciences 2, n. 3 (24 dicembre 2019): 418–25. http://dx.doi.org/10.31817/vjas.2019.2.3.02.
Testo completoAbstract (sommario):
The purpose of this study was to apply the modified Kostiakov method to determine the soil infiltration rate and permeated water amount of Thuong River alluvial soil for orange plantations in Lang Giang district, Bac Giang province, Vietnam. The soil particle size ranged from 0.02 to 2.00mm mainly found in the surface horizon (>77.7%). The soil was slightly acidic in the surface horizon, and highly acidic in the subsurface horizons (pHKCl from 3.42 to 4.79). The organic matter content of the surface horizon was mederate, while it was very low in the other horizons. The total nitrogen (N) content was low (0.15%) in the surface horizon and very low in the subsurface horizons (0.02-0.06%) while the available N was medium. The total phosphorus (P) content in the surface horizon was high (0.4%) and medium in the other horizons. Available P in the surface horizon was high (18.6mg per 100g soil) and decreased in lower depths to only 0.3mg per 100g soil in the deepest (5th) horizon. The total and available potassium measurements were very low. A filtration characteristic model was developed by using the modified Kostiakov method for alluvial soil. The constant values a, a, and b of the equation y = ata + b were 0.8035, 0.758, and 0.00346, respectively, which were smaller than 1. The average percentage difference between the actual and calculated values by the model was only 0.141%, indicating that the calculated values can accurately predict the actual data measurements in the field.
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Grumiller, D., M. M. Sheikh-Jabbari e C. Zwikel. "Horizons 2020". International Journal of Modern Physics D 29, n. 14 (9 settembre 2020): 2043006. http://dx.doi.org/10.1142/s0218271820430063.
Testo completoAbstract (sommario):
Horizons of black holes or cosmologies are peculiar loci of spacetime, where interesting physical effects take place, some of which are probed by recent (EHT and LIGO) and future experiments (ET and LISA). We discuss that there are boundary degrees of freedom residing at the horizon. We describe their symmetries and their interactions with gravitational waves. This fits into a larger picture of boundary plus bulk degrees of freedom and their interactions in gauge theories. Existence and dynamics of the near horizon degrees of freedom could be crucial to address fundamental questions and apparent paradoxes in black holes physics.